During inspiration,the diaphragm

An $A$ in the pulmonary volume $B$ the intra-pulmonary pressure to less than the atmospheric pressure which forces the air from $C$ to move into the lungs,i.e.,$D$. Choose the correct options for the blanks $A, B, C$ and $D$ to complete the above statement with reference to $NCERT$ textbook.

What structures are responsible for the breathing process?

State whether the given statements are true or false.
$I.$ Ventilation in humans is an active process.
$II.$ Diaphragm helps in generating the pressure gradient in the lungs.
Choose the correct option.

The intake and output of air from the lungs is helped by

Assertion : Inspiration occurs due to muscular relaxation.
Reason : During inspiration,the diaphragm and external intercostal muscle contract simultaneously.